Simulation of the progressive failure of an embankment on soft soil

A pragmatic strain-softening constitutive model, which is based on Modified Cam Clay, was applied to the simulation of the progressive failure of an embankment constructed on a deposit of sensitive (strain-softening) clay in Saga, Japan. A comparison of the predictions for this case indicates that if softening is ignored, only relatively small deflections and consolidation settlements are predicted, especially after construction. In contrast, for the case where softening is included in the analysis, progressive failure within the clay induces large shear deformations and finally failure of the embankment is predicted. This comparison suggests that softening-induced progressive failure should be considered in the design of embankments on such soils, and the residual strength of the deposit may have an important influence on the overall factor of safety of the construction. Detailed analyses of predicted excess pore water pressures, shear strains and shear stress levels in the ground indicate that considering the strain-softening process: (a) is associated with the buildup of excess pore water pressure; (b) promotes strain localization; and (c) results generally in a larger zone of soil involved in the failure.     

找矿方式及其在应用中要注意的问题

“找矿方式”是指技术上采用什么观点和方法手段进行找矿活动,大体上可分为“经验式”、“成因式”、“技术式”和“信息式”。经验式主要依靠直接或间接标志找矿,不太深究标志的成因;成因式则试图通过对找矿标志的成因解释以使其具有普遍意义,进而指导找矿;技术式侧重于研制某种适当的技术方法,用以寻找矿床;信息式不拘泥于上述任何一种找矿方式,而是强调借助数字化技术对各类找矿信息进行综合分析。上述各种方式均在找矿实践中发挥着作用,但也都存在着这样那样的难题。无论选择何种方式,对下述三个方面必须有清醒认识,否则可能会事与愿违甚至造成经济损失。其一,矿床成因研究探索性极强,勘查者要对研究成果客观评价并恰当应用。其二,地质找矿实践性极强,不能把一些必要的基础地质工作和经验性认识混同于矿床成因研究和成矿理论。其三,地质找矿工作是项复杂的系统工程,所选择的技术方式应该视工作进展情况和实际需要而变化。这凸现出能对各种观测资料、成因观点和技术手段作出综合评价的集成信息系统的重要作用。     

川藏公路中段地质灾害现象的航空遥感研究

川藏公路巴塘至林芝段位于我国青藏高原东南部,该地区是现今地壳运动十分强烈的地区之一,地形起伏强烈,气候变化多样,因此地质灾害十分发育,川藏公路就穿过这样一个复杂的地区。为查明公路沿线的地质灾害分布情况,90年代初,地矿部航空物探遥感中心沿川藏公路进行了彩色红外航空摄影,比例尺为1∶6万。通过彩色红外航片的解译及野外实地观测,圈定出滑坡、泥石流及崩塌等灾害现象,并对这些灾害的强度、活动性及其对公路的影响进行分析,最后对灾害成因及治理方法提出了建议。     

某金铜矿工艺矿物学研究

通过对某铜矿进行工艺矿物学研究,查明矿石中铜的赋存状态及综合利用可行性等。研究结果表明:主要赋存于黄铜矿、孔雀石中,可伴生回收金。该结论为选矿工艺流程提供依据,以期获得更好回收指标及综合开发利用价值。     

炎可宁丸质量评价研究

目的：建立炎可宁丸质量标准。方法：采用显微鉴别法鉴别黄连。采用薄层色谱法（TLC）鉴别黄柏、大黄、黄芩、板蓝根、黄连。采用高效液相色谱（HPLC）法测定大黄素与大黄酚的含量,使用Phenomenex Luna C₁₈色谱柱（4.6 mm ×250 mm,5μm）,以甲醇-0.1%磷酸溶液（85∶15）为流动相,流速为1.0 ml/min,柱温为30℃,检测波长为254 nm。采用HPLC法测定黄芩苷的含量,使用CAPCELL PAK C₁₈色谱柱（4.6 mm×250 mm,5μm）,以甲醇-0.1%磷酸溶液(45∶55)为流动相,流速为1.0 ml/min,柱温为30℃,检测波长为280 nm。结果:薄层色谱斑点清晰;大黄素和大黄素酚的线性范围分别为9.3～465.0 ng、11.6～580.0 ng,加样回收率分别为93.3%、98.0%,RSD分别为1.8%、2.7%;黄芩苷的线性范围为68～3400 ng,加样回收率为97.2%,RSD为1.2%。结论:本法简便可靠、结果准确,可用于该制剂的质量控制。     

基于多因素定量分析的农村居民点用地整理可行性研究

开展农村居民点用地整理是保护耕地资源、拓展建设用地空间、提高土地节约集约利用水平的重要实现途径,而项目的严格把关、科学决策是工作顺利推进的重要保障。以可行性研究为切入点,围绕准入基础和约束条件两大方面,尝试构建了由4个自然准入基础指标、3个经济准入基础指标、3个社会准入基础指标组成的准入评价指标体系和由4个生态环境影响指标、3个经济收益水平指标、4个社会服务功能指标组成的约束评价指标体系,从多因素、定量化角度对农村居民点用地整理项目的可行性进行全方位评价,实现从源头上开展科学评估、规避潜在风险。结合山东省淄博市桓台县马桥镇的农村居民点用地整理项目进行了评价应用和检验,具有普适性和推广性。     

Closing the “Hole in the Sky”: The Use of Refutation-Oriented Instruction to Correct Students' Climate Change Misconceptions

This article discusses the implementation of a pedagogical tool aimed at the refutation of secondary school (grade ten-equivalent) students' persistent climate change misconceptions. Using a lesson study approach, the materials and intervention techniques used were developed collaboratively with geography teachers. The objective is two-pronged: to closely monitor how children learn through refutation-oriented approach and to document how teachers process the experience. A pretest and post-test comparison showed that there was significant improvement in the students' climate change conceptual understanding following the intervention.     

Color map design for visualization in flood risk assessment

Visualizations of flood maps from simulation models are widely used for assessing the likelihood of flood hazards in spatial planning. The choice of a suitable type of visualization as well as efficient color maps is critical to avoid errors or bias when interpreting the data. Based on a review of previous flood uncertainty visualization techniques, this paper identifies areas of improvements and suggests criteria for the design of a task-specific color scale in flood map visualization. We contribute a novel color map design for visualizing probabilities and uncertainties from flood simulation ensembles. A user study encompassing 83 participants was carried out to evaluate the effects of this new color map on user’s decisions in a spatial planning task. We found that the type of visualization makes a difference when it comes to identification of non-hazardous sites in the flood risk map and when accepting risks in more uncertain areas. In comparison with two other existing visualization techniques, we observed that the new design was superior both in terms of task compliance and efficiency. In regions with uncertain flood statuses, users were biased toward accepting less risky locations with our new color map design.     

成矿过程中流体的作用及其主要研究方法

流体在成矿过程中扮演着十分重要的角色,它是成矿物质得以活化、迁移、富集的主要介质,同时流体的运移还能扩展有利的成矿空间,同位素地化学方法仍然是成矿流体研究的主要手段,实验地球化学、元素地球化学以及现代岩石学和矿物学研究方法在探讨流体的起源、演化等方面已发挥越来越重要的作用。每种方法均有其局限性,在实际工作中强调多种研究方法的结合十分必要。     

电偶源瞬变电磁测深研究（三）——大地表面瞬变电磁场

由逆拉普拉斯变换将均匀大地面上的电偶极子源谐变电磁场转换为瞬变电磁场,并计算出B_z(t)/t瞬态曲线;对分层大地面上的瞬变电磁场,采用折线逼近法计算余弦变换得出H_z(t)瞬态曲线。从计算结果分析可知,瞬变电磁测深可实现较小极距探测较大深度。